prize1-2, Exercise 2: A mountain temperature

Model answer:

1,300 metres is 1.3 kilometres. 1.3 x 6.5 = 8.45 degrees of cooling. 12 - 8.45 = about 3.5 degrees C at the top.
A real figure might differ because 6.5 degrees per kilometre is an average from a standard atmosphere; the actual rate depends on moisture and conditions, and the mountain's own surface, cloud and wind also affect the reading.